Haemothorax is the presence of blood in the pleural space, which can be caused by trauma, iatrogenic injury and other diseases [1]. As a subcategory of hemothorax, spontaneous hemothorax is much more rare, and sometimes caused by several self-diseases in the absence of trauma or atrogenic injury, but the data was only limited to case reports or case series [1]. We hereby report a case of spontaneous hemothorax in a patient with chest PNET who underwent an emergency thoracotomy.
PNET is an aggressive malignant tumor comprised of small round cells of putative neuroectodermal origin [2]. Occasionally, peripheral PNET was found in the thorax, affecting the ribs, sternum, scapula, clavicle and soft tissues of the chest wall and pleura [3]. The common symptom of chest PNET is the chest pain. However, with the enlargement of the tumor, chest tightness and dyspnea may occur [3]. In our case, the symptom occurs suddenly due to a life-threatening intra-thoracic hemorrhage as a result of spontaneous hemothorax. To our knowledge, there is only one case being reported with spontaneous hemothorax due to PNET in literatures [4], and our case was the second one, and also was the first one being reported in adult patients.
The mechanism of bleeding caused by PNET in chest is unclear. In our case, the bleeding may result from the nourishing vessels’ injury associated with rupture of the damaged pedicle caused by the traction of tissue adhesion and long term friction between the tumor and peripheral tissues. Previous literature told us that the pneumothorax may easily occur near the lower lobe and visceral pleura as a result of lung injury caused by rib exostoses, because the respiratory motion of the lower lobe is much more significant than that of the right other lobes [5]. The cause of bleeding in our case may be explained with similar mechanism.
In conclusion, the clinicians should keep in mind that the PNET is one of rare cause of spontaneous hemothorax, although the bleeding mechanism is unclear.